In a number of applications, it can be important to know an operating state of a work machine. The operating state can be used for automatically controlling components of the work machine. For example, in a construction machine or agricultural harvesting machine, an engine speed can be automatically set to idle when the operation state is detected as being “inactive” for a predetermined time (U.S. Pat. No. 8,230,667 B2). Another example is a combine with an automatic controller that needs to know whether the crop flow has become stable after an operating parameter of the combine has been altered or a combine with a number of vibration sensors that needs to know whether the combine is in an operating state in which it is appropriate to record vibration signals for subsequent fault detection of operating parts (US 2006/0276949 A1). The detected state can also be recorded for documentation and/or accounting purposes.
The system according to the mentioned prior art documents fuses values from a number of sensors to determine the operating state of the machine that may vary over the time. However, for numerous reasons signals from one such sensor can be less reliable than those from another sensor, be it due to the type of sensor or due to the operating state. For example, grain loss sensors are less reliable in high throughput conditions or in wet grain than in low throughput conditions or in dry grain. Since this is not considered in the prior art operating state detection system, its output is not always reliable.